We are requesting funds for a Precision X-Rad 320 Biological Irradiator. This instrument will provide 450kB high stability, high frequency x-rays, providing a highly reproducible and coherent irradiation field. There are numerous research projects at NYULMC that rely on the ability to deliver controlled irradiation to experimental rodents housed within the barrier vivarium. Due to Hurricane Sandy, the irradiator in the Smilow Central Animal Vivarium was destroyed. The vivarium is being reconstructed in the West Tower of the Alexandria Center. Availability of an animal irradiator is vital for ongoing projects on animals to be housed in this vivarium. A major advantage of the requested instrument is its reliance on an x-ray tube as a radiation source, rather that the more traditional isotope irradiators that contain radioactive cesium or cobalt. Thus, the X-Rad 320 lacks the major Homeland Security concerns inherent in maintaining a radioisotope-based irradiator, greatly simplifying installation, use, and oversight. The Precision X-Rad 320 will be placed within a shared procedure space within the West Tower Vivarium, where is will be available for use by the laboratory staff of the major user group, as well as ancillary minor users. The unit will be under the oversight of the Division of Laboratory Resources of the Office of Science and Research. It will be directly administered by the PI of this application, Assoc. Dean David Levy and his administrative staff in the Office of Collaborative Science. The major and minor user group comes from numerous academic departments and represents both basic and translational research areas, such as, cancer, immunology, infectious diseases, cardiology, inflammation, and DNA repair. The NIH funded users combined will use 75% of the instrument capacity. Remaining instrument capacity will be made available to any researcher with animals housed in the vivarium through an on-line scheduler. These investigators will be largely newly-recruited junior faculty who are gathering data in support of their first submissions to NIH. The availability of this instrument in a Core setting will make it fully available to all users, includng future users as they acquire NIH funding and research needs of animal irradiation. Although there are other animal irradiators on campus, the special needs of research on animals housed under barrier conditions require that each barrier vivarium have its own irradiator. Therefore, there is no substitute for a dedicated irradiator such as this within the West Tower Vivarium.